Automatic tool changing apparatus

ABSTRACT

In an automatic tool changing apparatus adapted for application to a machine tool having a vertical spindle, an intermediate tool transfer device is operable for removing a tool from a tool storage magazine of the apparatus by horizontal movement thereof and for subsequently positioning an axis of the removed tool parallel with the axis of the vertical spindle by the downward swinging motion thereof through 90°. Then a tool transfer device carries out exchanging the tool held in the intermediate tool transfer device for an already used tool held in the vertical spindle.

This is a division of application Ser. No. 387,002 filed Aug. 9, 1973now U.S. Pat. No. 3,893,227 issued July 8, 1975.

The present invention relates to an automatic tool changing apparatusand more particularly, relates to an automatic tool changing apparatusadapted for application to a machine tool having a vertical spindle.

In a machine having a vertical spindle, it is well known to use anautomatic tool changing apparatus to exchange an already used tool heldin the spindle of the machine for one of a plurality of tools stored ina tool storage magazine.

The arrangement of a known automatic tool changing apparatus is suchthat when a tool stored in the tool storage magazine is to be insertedin the vertical spindle, the tool magazine is indexed by a tool indexdevice to a predetermined position where the tool is inserted in a readystation by a sub-arm. Subsequently, the ready station is swung downwardby 90° to a position where the new tool in the ready station can beexchanged for a used tool which is in the vertical spindle. Then, thenew tool in the ready station and the used tool in the vertical spindleare grasped and rotated, through 180°, by a main arm so that the newtool may be inserted in the vertical spindle. In such an arrangement,the ready station interposed between the sub and main arms has beenindispensable.

Therefore, an object of the present invention is to provide an automatictool changing apparatus which eliminates provision of a ready station soas to simplify the arrangement thereof.

According to the present invention, an automatic tool changing apparatusadapted for application to a machine tool having a vertical spindlecomprises a rotatable tool storage magazine adapted for storing aplurality of tools, an intermediate tool transfer device for taking atool out of the storage magazine by horizontal movement thereof and forsubsequently positioning an axis of the tool parallel with an axis ofthe vertical spindle in a position adjacent to said vertical spindle bydownward swinging motion thereof through 90°, and a tool transfer devicefor exchanging the tool in the intermediate tool transfer device for analready used tool held in said vertical spindle.

The above and other objects, and advantages of the present inventionwill readily be understood from the ensuing description of a preferredembodiment with reference to the accompanying drawings wherein:

FIG. 1 is a front elevation view of a machine tool provided with anautomatic tool changing apparatus according to the present invention;

FIG. 2 is a side elevation view of FIG. 1;

FIG. 3 is a cross sectional view taken along the line III--III of FIG.2;

FIG. 4 is a cross sectional view taken along the line IV--IV of FIG. 1;

FIG. 5 is a cross sectional view taken along the line V--V of FIG. 1;

FIG. 6 is an enlarged cross sectional view taken along the line VI--VIof FIG. 5;

FIG. 7 is a partial and enlarged cross sectional view of a tool storagemagazine illustrating a state in which a tool sleeve in the tool storagemagazine is grasped by an intermediate tool transfer device;

FIG. 8 is a cross sectional view taken along the line VIII--VIII of FIG.7.

Referring to FIGS. 1 and 2, there is shown a machine tool having a bed1, on the upper surface of which guide ways 2 are formed. On the guideways 2, a saddle 3 is mounted so that it may be moved by a drivemechanism including a feed motor 4 and a gear box 5. Saddle 3 isprovided with guide ways 6 formed on the upper surface thereof. Aworktable 7 on which a workpiece to be machined is fixed, is mounted onthe guide ways 6 so that table 7 may be moved by another drive mechanismincluding a feed motor 8 and a gear box 9, in the direction orthogonalto the direction of movement of saddle 3.

At the rear of the bed 1, a column 10 stands which is formed integrallywith bed 1 and has guide ways 11 formed on a front face thereof.

A spindle head 14 is vertically slidably mounted on the guide ways 11above the worktable 7, and the vertical movement of the spindle head 14with respect to worktable 7 is controlled by a feed mechanism includinga feed motor 21. The spindle head 14 is provided with a spindle 20 whichis vertically and rotatably journaled in said spindle head 14 and inwhich one of various kinds of tools stored in a later described toolstorage magazine can be selectively inserted. A tool transfer device 12for a tool 30 and an intermediate tool transfer device 13 fortransferring the tool 30 between the tool transfer device 12 and thetool storage magazine 23, are provided for the machine tool so as to bepositioned under the spindle head 14. At a side of the column 10, ahousing 17 is supported by a pair of pilot bars 19 to be movable in ahorizontal direction perpendicular to the direction of the axis ofvertical spindle 20. The capability of horizontal movement of thehousing 17 is provided by means of a cylinder 24 for removing andinserting a later described tool sleeve into tool storage magazine 23.The tool storage magazine 23 is mounted on the housing 17 by means of amain rotating shaft 26 so as to be capable of rotating in a planeparallel to the axis of vertical spindle 20, and as seen best from FIG.1, tool storage magazine 23 has an outermost periphery where a pluralityof tool sleeves 29 are removably mounted. Each of the tool sleeves 29 onthe tool storage magazine 23 holds a tool 30 which is removably insertedin the tool sleeve 29 so that the axis thereof is directed perpendicularto the axis of spindle 20. Further, the tool storage magazine 23 isrotated and indexed, by means of an appropriate index device provided inhousing 17, to a predetermined tool removal position where a selectedtool 30 required for the next machining operation is removed from toolstorage magazine 23.

FIGS. 7 and 8 illustrate a tool holder gripping device provided for thecircumference of two circular magazine plates 27a, 27b of said toolstorage magazine 23. In FIGS. 7 and 8, the front and rear circularmagazine plates 27a, 27b fixedly mounted on the main rotating shaft 26can carry out three motions of forward and reverse rotations and stop ofthe rotations under control of a feed motor (not shown) associated withthe main rotating shaft 26 and an appropriate index mechanism (notshown). The two circular magazine plates 27a, 27b are further providedwith respective opening portions 28a, 28a and support ends 28b, 28b ofarc shape for supporting tool sleeves 29 received from the openingportions 28a, 28a, which are equidistantly formed in the circumferenceof said both plates 27a, 27b. Tool 30 together with a holder for holdingthe tool 30 is fitted in tool sleeve 29 so that a pull stud 120 ispositively engaged with spring-loaded detent pins 25 provided in toolsleeve 29. The tool sleeve 29 itself is provided with the outer roundsurface fitting in support ends 28b, 28b so as to be rigidly held byboth magazine plates 27a, 27b. The tool sleeve 29 is also provided withtwo recesses 121 of rectangular cross sections which are formed in thefront portion thereof so that it is readily removed from and insertedinto tool storage magazine 23 by intermediate tool transfer device 13without interferring with the two opening portions 28a. That is to say,the two recesses 121 of tool sleeve 29 are formed so that they may bealigned with opening portions 28a of front magazine plate 27a when thehousing 17 is withdrawn by cylinder 24 and as a result, the interferencebetween tool sleeve 29 and the opening portion 28a of front magazineplate 27a can be avoided when the tool sleeve 29 is removed from orinserted into tool storage magazine 23. It should be noted that thewithdrawal of housing 17 also makes it possible to avoid inteferencebetween tool sleeve 29 and the opening portion 28a of rear magazineplate 27b since the opening portion 28a of rear magazine plate 27b comesto the outside of the rear end of tool sleeve 29. From FIG. 7, it willalso be seen that tool sleeve 29 is provided with a setting hole 122formed in the part which faces tool storage magazine 23, and the settinghole 122 is engaged with a spring-loaded detent pin 124 provided for adetent block 123 secured to the above-mentioned two magazine plates 27a,27b so that rigid support of tool sleeve 29 in tool storage magazine 23may be completed. Further, tool sleeve 29 is also provided with verticalholes 125 formed in the upper and lower surfaces thereof and with whichprojections 44a of later described clamp fingers 44 of intermediate tooltransfer device 13 vertically engage between two front and rear magazineplates 27a, 27b so that intermediate tool transfer device 13 is capableof clamping tool sleeve 29 upon transferring to tool 30 together withthe tool sleeve 29.

The intermediate tool transfer device 13 will be explained in detailwith reference to FIGS. 3 and 4.

A body 33 of an intermediate tool transfer device 13 is secured to aside of the column 10 of the machine tool. The body 33 is provided withtwo parallel through-bores 34 and 35 formed therein to be orthogonalwith both centers about which spindle 20 and tool storage magazinerotate respectively. In the through-bore 34, a shaft 38 is inserted byway of a bush member 36 to be rotatable about and slidable along theaxis of the through-bore 34. The shaft 38 is provided with teeth 46formed in one end (rear end) thereof and serving as a pinion. As isshown in FIG. 3, the pinion teeth 46 are longitudinally extended alongthe axis of shaft 38 in order that engagement of the pinion teeth 46with a later described rack 53 can be maintained even if shaft 38carries out sliding movement in the direction along the axis thereof.The shaft 38 is also provided with an extension 40 formed in the frontend thereof. The extension 40 is provided with a connecting member 42mounted thereon in a state such that the extension 40 is free to rotaterelative to the member 42. This connecting member 42 is provided with anextended part in which the connecting member 42 is connected with anextension 41 of a guide rod 39 which is slidably fitted in thethrough-bore 35 by way of a bush 37. Further, it is shown that a sub-arm43 hangs on shaft 38 through the firm connection of one end of thesub-arm 43 with the extension 40 of shaft 38.

The sub-arm 43 is provided with clamp fingers 44 for releasably clampinga tool sleeve 29 and tool 30 held in the tool sleeve, which are storedin tool storage magazine 23, the clamping action of clamp fingers 44being driven by a cylinder 45. A cylinder 15 is secured to the rear partof the body 33 by means of bolts and screws so that a longitudinal axisof the cylinder 15 is concentric with the central axis of thethrough-bore 34. The cylinder 15 is provided with a piston 48 slidablyinserted in the internal bore of cylinder 15 and having a piston rod 49extending from an internal end of the piston 48. Said piston rod 49 isconnected to the rear end of the shaft 38. An outer end of piston 48 isprovided with a dog bar 47 threadedly connected thereto, and the dog bar47 has dogs (not shown) which are threadedly mounted on the bar 47 andare engageable with limit switches (not shown) so as to define thelimits of advance and return of the piston 48. These advances andreturns of the piston 48 result in the sliding of the shaft 38 withinthe through-bore 34 in the longitudinal axial direction.

Referring to FIG. 4, the body 33 is also provided with a cylinder bore16 formed therein in a direction perpendicular to the through-bore 34.The cylinder bore 16 is provided with a piston 52 slidably inserted inthe bore 16 and having rack 53 which are formed in the outer surface ofthe piston 52. The rack 53 is engaged with the pinion 46.

Caps 102 and 103 are attached to the opposite ends of the cylinder bore16 so as to close the bore. The cap 102 is provided with a stop 55threaded therein. This stop 55 is arranged so that it is capable ofmeeting a projection 54 formed on one end of the piston 52. A dog bar 56projects from the other end of the piston 52, and this dog bar 56 hasthreaded thereon dogs 57 and 58 which are engageable with limit switches115 and 116 for defining the limitations of the advance and return ofthe piston 52.

The tool transfer device 12 will now be described with reference toFIGS. 1, 2, 5, and 6. Briefly, the tool transfer device 12 operates in amanner such that when it grasps a used tool 30 held in the spindle 20and a subsequent working tool 30, which is inserted in a tool sleeve 29and is transferred to the tool change position together with the sleeve29, it carries out vertical downward movement until the respective toolsare completely removed from spindle 20 and the tool sleeve 29. Afterthis the tool transfer device 12 turns about its vertical axis through18 degrees while holding both tools 30. Then, the device 12 carries outvertical upward movement until the subsequent working tool 30 isinserted in the spindle 20. After completion of the insertion of thetool in the spindle 20, the tool transfer device leaves spindle 20 sothat the machine tool can start a subsequent machining process.

Referring to FIGS. 5 and 6, the body 59 of the tool transfer device 12is secured to a side of the previously described spindle head 14, and isprovided with a through-bore 60 and a cylinder bore 81 formed therein.These two bores extend in parallel with each other and also in parallelwith the vertical axis of spindle head 14. A slide sleeve 62 is fittedin the through-bore 60, by way of a bush 61, so as to be free to slidevertically. The slide sleeve 62 is provided with a longitudinal bore 63extending along the central axis of the sleeve 62, a flange part 62aformed in the lowermost end thereof, and a cylinder bore 70 formed inthe uppermost end thereof. The flange part 62a is provided with a mainarm 104 fixedly connected thereto which has a pair of pawls 79 and 80for clamping tools 30. The main arm 104 is provided with a pair of slidemembers 74 and 75 which are both slidably fitted within the main arm104. Each of the slide members 74 and 75 has racks formed in itsopposite side faces, and the sliding movements of slide members 74 and75 are accompanied by clamping and releasing motions of pawls 79 and 80.The through-bore 63 of slide sleeve 62, which has a diameter smallerthan that of cylinder bore 70, is provided with a movable bar 64inserted therein. The movable bar 64 has an upper end connected to thepiston 105 within the cylinder bore 70. The connection between themovable bar 64 and the piston 105 is attained by tightening a nut 118engaged with a screw thread of movable bar 64. The lower end of movablebar 64 has a connecting member 66 pivotally linked thereto, by means ofa pivotal pin 76. The connecting member 66 is also pivotally linked to apair of other connecting members 72 and 73, by means of a pivotal pin106. The connecting members 72 and 73 are pivotally linked to the slidemembers 74 and 75, respectively. The above-mentioned upper end of themovable bar 64 is provided with a dog bar 67 which extends verticallyupward and has a screw thread part in its uppermost end. Dogs 68 and 69,which respectively operate a limit switch 71 defining the limits ofadvance and return of piston 105, are adjustably engaged with the screwthread part of dog bar 67, respectively. Therefore, adjusting thepositions of dogs 68 and 69 along dog bar 67 allows adjustment of themagnitude of the vertical movement of the piston 105.

The slide sleeve 62 is provided with teeth 65 formed in the outersurface thereof and serving as a pinion. The pinion teeth 65 engagingwith a later described rack 91, extend longitudinally in the axialdirection of the sleeve 62 so that the vertical sliding of the sleeve 62may not cause disengagement between pinion teeth 65 and the rack 91.

The cylinder bore 81 is closed by caps 107 and 108 attached to theopposite ends thereof, and is provided with a piston 82 slidablyinserted therein. The piston 82 is provided with a piston rod 83 whichis formed so as to be integral with the piston 82 and has an uppermostend to which an extension 84 of a connecting member 85, fixed to theabove-mentioned sleeve 62, is fixedly connected. Further, as shown inFIG. 5, the extension 84 is provided with a front edge which is formedso as to be engageable with limit switches 86 and 87 for defining thelimits of vertical upward and downward movements of piston 82, the limitswitches being secured to the spindle head 14.

As is shown in FIG. 6, the body 59 of the tool transfer device 12 isfurther provided with a cylinder bore 22 formed therein in such a mannerthat the longitudinal axis of the bore 22 is orthogonal with that of thebore 60. In the cylinder bore 22, a piston 90 having a rack 91 isslidably inserted. The rack 91 of the piston 90 engages with the pinionteeth 65 of the sleeve 62 in the bore 60. Caps 109 and 110 respectivelyfixed to the opposite ends of the cylinder bore 22, close the bore 22and are provided with stops 95 and 94 secured in the caps 109 and 110,respectively. These stops 95 and 94 are arranged so as to meetrespective projections 93 and 92 provided at opposite ends of the piston90.

Supports 111 and 112 are provided for body 59 of the tool transferdevice 12, and slidably support actuating rods 97 and 98, respectively.Respective actuating rods 97 and 98 are provided with their lower endsplaced in a groove 96 which is formed in the piston 90 so as to extendalong the axis of said piston 90 while having longitudinally spaced ends96a and 96b. The actuating rods 97 and 98 are further provided withupper ends projecting from supports 111 and 112, and contacting limitswitches 99 and 100 secured to body 59 by means of brackets 113 and 114.Thus, it will be noted that actuating rod 97 or 98 is pushed upwardly byend 96b or 96a of groove 96, depending upon the sliding of piston 90and, as a result, limit switch 99 or 100 is operated by actuating rod 97or 98. That is to say, the limits of sliding movement of piston 90 aredefined by the operation of limit switches 99 and 100. It should benoted that the above-mentioned stops 94 and 95 are adjusted so thatpiston 90 may not slide to the extent that it exceeds the limits.

The tool change operation of the apparatus according to theabove-mentioned arrangement will now be explained.

When a used tool 30 being held in spindle 20 should be exchanged for asubsequent tool 30 in tool storage magazine 23, cylinder 45 ofintermediate tool transfer device 13 is first operated, and clampfingers 44 clamp the tool sleeve 29 holding the subsequent tool 30stored in the tool storage magazine 23.

Then, cylinder 24 is operated so as to horizontally pull back housing 17together with the tool storage magazine 23 until the opening 28a of thefront magazine plates 27a aligns with recess 121 of the tool sleeve 29clamped by clamp fingers 44 of the intermediate tool transfer device 13.In addition, the rear magazine plate 27b is separated from the rear endof the tool sleeve 29. Subsequently, pressurized oil is applied to theleft chamber of cylinder 15, so as to move piston 48 rightwards. As aresult, sub-arm 43 of device 13 is horizontally moved in the outwardlyradial direction of the tool magazine 23 so that the tool sleeve 29together with the subsequent tool 30 are removed from the tool storagemagazine 23. When piston 48 comes to the end of its rightward movement,piston 52 of cylinder 16 is subsequently advanced, so that sub-arm 43 isrotated by means of rack 53, pinion 46 and shaft 38, through 90 degreesin a counterclockwise direction in FIG. 2. Thus, the above-mentionedtool sleeve 29 and the subsequently tool 30, which are held by clampfingers 44 of sub-arm 43, come into a position in which the axes of boththe tool sleeve 29 and the tool 30 are in parallel with the axis ofspindle 20, and wait these for the next tool change operation.

When the tool 30, being held in spindle 20, completes its working and acommand for a tool change operation is provided for the apparatus, therotational motion of spindle 20 is stopped. Then, the spindle head 14 islifted up until the used tool 30 held in spindle 20 comes to the toolchange position. When spindle head 14 is lifted up to the uppermost endthereof, piston 105 of cylinder 70 is operated to move downward in FIG.5. Together with piston 105, movable bar 64 is also moved in the samedownward direction as a result, pawls also moved in the same downwarddirection. As a result, pawls 79 and 80, provided at the opposite endsof main arm 104, are driven by means of connecting members 66, 72, and73, and slide members 74 and 75 to grasp the subsequent tool 30 held inthe tool sleeve 29 awaiting the tool change and the used tool 30 held inthe spindle 20. The grasp of both tools 30 by pawls 79 and 80 of mainarm 104 is confirmed by confirmation of completion of the downwardmovement of movable bar 64 by limit switch 71. If the confirmation isprovided by operation of limit switch 71, pressurized oil is fed intocylinder 81 through a supply port 88 so as to move piston 82. Therefore,pawls 79 and 80 grasping the subsequent tool and the used tool are moveddownwards along the axis of spindle 20 by means of connecting member 85and slide sleeve 62. As a result, the used tool 30 and the subsequenttool 30 are removed from the tool sleeve 29 and spindle 20,respectively. When pawls 79 and 80 are moved downwards until the edge ofthe extension 84 pushes and actuates limit switch 87, main arm 104 isstopped in its downward movement. When the downward movement of main armis confirmed by operation of limit switch 87, pressurized oil is fed tocylinder bore 22 so as to move piston 90. The movement of piston 90causes the main arm 104 to rotate 180° via rack 91, pinion teeth 65 andsleeve 62. Thereafter, pressurized oil is fed to the lower chamber ofcylinder 81 to move piston 82 upwards and thereby pull back main arm104. As a result, the subsequent tool 30 is inserted in the spindle 20and the used tool 30 is inserted in the tool sleeve 29 clamped by clampfingers 44 of the intermediate tool transfer device 13. Subsequently,the grasps of both tools 30 by pawls 79 and 80 are released by thepulling back of piston 105 within cylinder 70. Then, piston 52 withincylinder 16 is pulled back to rotate sub-arm 43 of the intermediate tooltransfer device 13 in the clockwise direction in FIG. 2. Thereafter,pressurized oil is fed to the right chamber of cylinder 15 to movesub-arm 43 in the leftward direction so that the tool sleeve 29incorporating the above-mentioned used tool 30 is re-inserted in thetool storage magazine 23. After re-insertion of the tool sleeve 29together with the used tool 30, cylinder 24 is again operated tohorizontally advance tool storage magazine 23 so that support ends 28aand 28b of the front and rear magazine plates 27a and 27b engage withthe re-inserted tool sleeve 29 so as to support the sleeve 29. Then,cylinder 45 is operated to release the grasp clamp fingers 44 on thetool sleeve 29 holding the used tool.

The rotation of tool storage magazine 23 is then restarted so that atool sleeve 29 having a tool 30 which is to be used in the furthersubsequent machining operation, is indexed to the position where thetool sleeve 29 is removed from tool storage magazine 23. When the toolsleeve 29 together with the further subsequent tool 30 is indexed tothis position, cylinder 45 is again operated so that clamp fingers 44clamp the tool sleeve 29 holding the subsequent tool 30. Thereafter, thetool sleeve 29 and the tool 30 are brought to the tool change positionin the manner described above. During the above restarting of the toolchange for the further subsequent tool 30, spindle head 14 comes down toa position adjacent to a workpiece on worktable 7 and starts themachining operation to be carried out by the changed tool 30 in spindle20.

It will now be understood that the arrangement and the operation of theautomatic tool change apparatus according to the present invention, canprovide the following advantages.

i. As provision of a ready station is eliminated between the sub-arm ofthe intermediate tool transfer device 13 and the main arm of tooltransfer device 12, a decrease in the number of elements of theapparatus is provided, and simplification of the arrangement of theapparatus compared with the prior art and shortening of each toolchanging cycle can be attained.

ii. The symmetric arrangement of pawls 79 and 80 of the tool transferdevice 12 with respect to movable bar 64 enables equivalent forces to beexerted in the clamping of tools 30.

iii. The arrangement of horizontal movement of tool storage magazine 23can decrease the number of motions of the intermediate tool transferdevice 13 compared with the prior art.

What is claimed is:
 1. A tool transfer device for use in an automaticmachine tool for changing a used tool and a new tool comprising:aslideable sleeve; a body having means for mounting the slidable sleeveon the machine tool; a main arm fixedly mounted on said slideable sleeveand provided with a first and second pawl means, said first pawl meansfor grasping the used tool and said second pawl means for grasping thenew tool; a first power means operable to actuate said first and secondpawl means to grasp said new and used tools; a connecting meansconnecting said first power means to said pair of pawl means forsimultaneously actuating said pair of pawl means in response to theoperation of the first power means, said connecting means comprising apair of slide members slidably mounted in said main arm to be operablyconnected to said pair of pawl means, a pair of pivotal connectingmembers pivotably connected to said pair of slide members, and a furtherpivotal connecting member having one end pivotably connected to bothsaid pair of pivotal connecting members, and; a second power means forrotating said slidable sleeve with said pair of pawl means so as tointerchange the positions of said used and new tools grasped by saidpawl means.
 2. A tool transfer device according to claim 1, wherein saidfirst power means comprises a fluid operated cylinder having a pistontherein, and a movable bar having one end connected to the piston andthe other end to which said further pivotal connecting member ispivotably connected, said movable bar being slidable in said slidesleeve means.
 3. A tool transfer device according to claim 2, whereinsaid fluid operated cylinder is provided with a rod extended therefromtoward the outside of said cylinder, the rod being movable with saidpiston of said cylinder, and wherein said device further comprises afirst confirmation means fixedly located at the outside of saidcylinder, the confirmation means being actuated by dog means mounted onsaid rod when said piston moves in said fluid operated cylinder wherebythe actuation of said pair of pawl means is confirmed.